Agriculturally active ingredients are often provided in the form of concentrates suitable for dilution with water. Many forms of agricultural concentrates are known and these consist of the active ingredient and a carrier, which can include various components. Water-based concentrates are obtained by dissolving, emulsifying and/or suspending agriculturally active technical materials in water. Due to the relatively complex supply chain for crop protection agents, such concentrate formulations can be stored for long periods and may be subjected during storage and shipping to extreme temperature variations, high-shear and repetitive vibration patterns. Such supply chain conditions can increase the likelihood of formulation failure due to, for example, water mediated degradation and stability problems.
Accordingly, the efficient use of aqueous systems with certain agrochemicals and crop protection agents is restricted due to their poor chemical stability when exposed to water during storage. Typically, hydrolysis is the most common water-mediated degradation mechanism; however, agricultural concentrates with water-sensitive active ingredients are also subject to oxidation, dehalogenation, bond cleavage, Beckmann rearrangement and other forms of degradation on exposure to water.
In some cases it may be desirable to combine different agrochemicals to provide a single formulation taking advantage of the additive properties of each separate agrochemical and optionally an adjuvant or combination of adjuvants that provide optimum biological performance. For example, transportation and storage costs can be minimized by using a formulation in which the concentration of the active agrochemical(s) is as high as is practicable and in which any desired adjuvants are “built-in” to the formulation as opposed to being separately tank-mixed. The higher the concentration of the active agrochemical(s) however, the greater is the probability that the stability of the formulation may be disturbed, or that one or more components may phase separate.
Another challenge arises where a user of an agrochemical liquid concentrate formulation dilutes the formulation in water (for example in a spray tank) to form a dilute aqueous spray composition. Such agrochemical spray compositions are widely used, but their performance sometimes can be limited by the tendency for certain agrochemicals to degrade in a spray tank on exposure to water. For example, agrochemical breakdown can increase with increasing alkalinity and water temperature, and with the length of time the spray composition is left in the tank.
In addition, it may be desirable to improve the effectiveness of the agrochemicals by controlling the release rate of agrochemical into the application site from the formulation. For agrochemicals that are to any significant extent soluble in water, this is a particular challenge if water is present in the formulation, because of the tendency of the agrochemical to come to thermodynamic equilibrium and partially dissolve within the formulation. To the extent that the agrochemical dissolves, this reduces the physical stability of the formulation and negates any controlled release properties.
In addition, spray tank mixes can contain a variety of chemicals and adjuvants that may interact and change the effectiveness of one or more of the agrochemicals included therein. Incompatibility, poor water quality and insufficient tank agitation can lead to reduced effectiveness of sprays, phytotoxicity and can affect equipment performance.
Considering the variety of conditions and special situations under which agrochemical liquid concentrate formulation are stored, shipped an used around the world, there remains a need for concentrate formulations of agrochemicals, including water sensitive agrochemicals, that provide stability benefits under at least some of those conditions and situations. There is a further need for such formulations having high loading that are stable when diluted with water under a wide range of field conditions.